Malocclusion in the Chinchilla

Malocclusion is unfortunately a very common disease and one many owners
misunderstand. It is extremely painful for the chinchilla and close observation
of your chinchillas can help to catch symptoms early.

There are several causes thought to be behind the disease. Among them are
genetics, poor diet/nutrition, lack of calcium and vitamin C, injury, lack
of items to chew on (toys, wood, etc.) for the front teeth, and lack of
sufficient fiber (hay) to help keep the back teeth ground down. Because
the disease can be genetically carried, it is recommended that no chinchilla
with known malocclusion ever be bred.

When the molar crowns overgrow, they can grow outward and/or curve inward.
Upper molar crowns tend to curve outwards and the lower molars tend to grow
inwards. Outward growth can cause tooth spurs, which will cut into and injure
the cheek tissue, creating pain and likely infection. Inward growth can
create sharp points that cut or even trap the tongue. Both of these make
eating nearly impossible and terribly painful.

Not only can the teeth themselves overgrow, but the roots of the teeth
as well. The roots can literally grow upwards into the eye sockets, or through
the jaw bone. Often at this point, they can be felt along the lower jaw
as bumps using your fingertips.

Malocclusion is usually a painful, often fatal condition. Early diagnosis
can buy some time to trim the teeth themselves, but cannot correct root
overgrowth. At the first sign of malocclusion, your chinchilla should be
seen by an experienced exotic veterinarian. Unfortunately most cases are
quite advanced by the time symptoms present themselves, making treatment
often difficult.

Included below are some radiographs (x-rays) of a normal chinchilla and
a severely maloccluded chinchilla. Normal radiographs are of my personal
chinchilla (Praline) taken 3/5/04 and the maloccluded radiographs are used
with permission, taken by the same veterinarian in February, 2004. Please
note that the radiographs for Praline are a bit dark, but are clear enough
to denote the differences.

Normal:

Maloccluded:

You can easily see the differences in this view. A normal chinchilla should
have a nice straight alignment of the back teeth with little to no curving
of the teeth or roots. The roots should be contained within the jaw bones,
not protruding.

The maloccluded chinchilla has clearly visible overgrowth of both the molars
themselves and the roots. The roots appear to be protruding into the eye
sockets and out from the lower jaw. It also appears that the bottom incisor
has been trimmed, probably due to overgrowth as well.

Normal:

Maloccluded:

In the normal view, you can see that the roots are nicely contained within
the proper areas. In the maloccluded view, you can see the teeth roots growing
outside of the jaw itself.

Normal:

Maloccluded:

In the normal view, you can clearly make out the eye sockets, a straight
line between top and bottom back teeth, and no visible overgrowth of the
roots.

In the maloccluded view, the eye sockets are nearly completely blocked
from sight by overgrowth of the tooth roots, no line is visible to distinguish
top jaw from bottom jaw, and the view of the jaw is barely visible due to
root overgrowth.

As you can see, left untreated this condition can be very painful to the
chinchilla and it will eventually starve to death. Sometimes the quality
of life can be improved by trimming the teeth and giving pain medication,
but not always. Once the roots overgrow to the degree pictured, a chinchilla
is in constant pain and you, as a loving guardian, should consider the quality
of the chinchilla's life and maybe discuss potential euthanasia with your
veterinarian.

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